Form-token-field generated from a custom taxonomy doesn't display proper labels

[stockhuman]

Describe the bug
Form inputs generated by custom taxonomies don't reflect the labels set in register_taxonomy(), instead defaulting to 'Add new Term" in the placeholder. Additionally, the hover pop-up when one goes to remove a term only describes it as a "Term" (ie: "Remove Term" instead of what's defined in the labels array).

To Reproduce
Steps to reproduce the behavior:

1. Register a REST-queryable taxonomy with custom labels
2. view the page/post/CPT that taxonomy is enabled for and go add a new term
3. See the placeholder text does not reflect the labels set in the taxonomy
4. See error

Expected behavior
One would expect to see the placeholder prop passed to the form so that "Add new Term" becomes, say, "Add a Byline".

Env:

• OS: Windows 10
• Browser: Firefox (and others?)
• Version: 61.0.2
• Gutenberg: 3.6.2

[youknowriad]

Related #8448

[youknowriad]

I think this is fixed by #10962